Method and apparatus with battery charging

ABSTRACT

A battery charging method and apparatus are provided. The battery charging apparatus determines, in a present charging operation, a variation in a charging current to charge a battery based on a degradation condition of the battery and an internal state of the battery in the present charging operation, and determines a charging current of a subsequent charging operation based on the variation in the charging current in the present charging operation and the charging current in the present charging operation.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 16/023,241, filed on Jun. 29, 2018, which claimsthe benefit under 35 USC § 119(a) of Korean Patent Application No.10-2017-0175522, filed on Dec. 19, 2017, in the Korean IntellectualProperty Office, the entire disclosure of which is incorporated hereinby reference for all purposes.

BACKGROUND 1. Field

The following description relates to a method and apparatus with batterycharging.

2. Description of Related Art

A battery is used as a power source for various devices and systems suchas, for example, mobile devices or electric vehicles, and variousschemes or methods for charging a battery have been proposed. Forexample, a constant current-constant voltage (CC-CV) charging scheme isgenerally used to charge the battery with a constant current until thebattery voltage reaches a predetermined voltage, and to charge thebattery with a constant voltage until the battery current reaches apreset low current. In other examples, a multi-step charging scheme,which charges a battery with a constant current in multiple steps from ahigh current to a low current, and a pulse charging scheme, whichrepeatedly applies or feeds a charge current to the battery in pulses,with short rest periods between pulses, are used.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, a battery charging method includes determining,in a present charging operation, a variation in a charging current tocharge a battery based on a degradation condition of the battery and aninternal state of the battery in the present charging operation; anddetermining a charging current of a subsequent charging operation basedon the determined variation in the charging current in the presentcharging operation and the charging current in the present chargingoperation.

The determining of the variation in the charging current comprisesdetermining the variation based on a rate of change of the internalstate of the battery in the present charging operation, and a differencebetween the internal state of the battery and the degradation condition.

The determining of the variation in the charging current furthercomprises determining the variation to increase in response to the rateof change of the internal state of the battery in the present chargingoperation increasing.

The determining of the variation in the charging current furthercomprises determining the variation to decrease in response to thedifference between the internal state and the degradation conditionincreasing.

The determining of the variation in the charging current comprisesdetermining the variation based on a state of charge (SOC) of thebattery.

The determining of the variation in the charging current includes inresponse to the SOC reaching a threshold condition, determining thevariation in the charging current based on the internal state of thebattery and the degradation condition, and in response to the SOC notreaching the threshold condition, determining the variation in thecharging current based on the SOC, the internal state of the battery,and the degradation condition, wherein the variation in the chargingcurrent is greater when the SOC has not reached the threshold condition.

The internal state of the battery comprises two or more of an anodeoverpotential, a cathode overpotential, an anode surface lithium ionconcentration, a cathode surface lithium ion concentration, a cellvoltage condition, an SOC and a temperature of the battery, and thedetermining of the variation in the charging current includesdetermining variations in charging currents for each of a plurality ofinternal states, and finally determining the variation in the chargingcurrent based on the determined variations for each of the plurality ofinternal states.

The determining of the variation in the charging current includesdetermining whether a charging limit condition is satisfied duringcharging of the battery in the present charging operation, anddetermining the variation in the charging current based on the internalstate of the battery and the degradation condition, in response to thecharging limit condition being satisfied.

The charging limit condition is a condition to divide charging of thebattery into a plurality of charging operations to charge the batterywithin a range in which a degradation of the battery is prevented.

The internal state of the battery is a factor that controls on thedegradation condition of the battery, and the internal state isestimated from one or more of a current, a voltage and a temperature ofthe battery based on an electrochemical model of the battery.

The electrochemical model is a model to which a degradation factor ofthe battery is applied.

The degradation factor comprises one or more of an anode surfaceresistance, a cathode surface resistance, a reduction in an anode activematerial and a reduction in a cathode active material.

The battery is charged with the charging current of the subsequentcharging operation.

The battery charging method includes determining whether one or more ofa charging time, a current, a voltage, a temperature and the internalstate of the battery reaches a charging termination condition, andterminating charging of the battery in response to the chargingtermination condition being satisfied.

According to another general aspect, a battery charging apparatusincludes a processor, and a memory configured to store at least oneinstruction that is executable by the processor, wherein in response tothe at least one instruction being executed by the processor, theprocessor is configured to determine, in a present charging operation, avariation in a charging current to charge a battery based on adegradation condition of the battery and an internal state of thebattery in the present charging operation, and configured to determine acharging current of a subsequent charging operation based on thevariation in the charging current in the present charging operation andthe charging current in the present charging operation.

The processor is configured to determine the variation in the chargingcurrent based on a rate of change of the internal state of the batteryin the present charging operation, and a difference between the internalstate of the battery and the degradation condition.

The processor is further configured to determine the variation in thecharging current based on a state of charge (SOC) of the battery.

The internal state of the battery comprises any two or any combinationof an anode overpotential, a cathode overpotential, an anode surfacelithium ion concentration, a cathode surface lithium ion concentration,a cell voltage condition, an SOC and a temperature of the battery, andthe processor is configured to determine variations in charging currentsfor each of a plurality of internal states, and to finally determine thevariation in the charging current based on the determined variations foreach of the plurality of internal states.

The processor is configured to determine whether a charging limitcondition is satisfied during charging of the battery in the presentcharging operation, and configured to determine the variation in thecharging current based on the internal state of the battery and thedegradation condition, in response to the charging limit condition beingsatisfied.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a battery system.

FIG. 2 is a flowchart illustrating an example of a battery chargingmethod.

FIG. 3 and FIG. 4 illustrate an example of a process of determining acharging current.

FIG. 5 illustrates an example of a process of determining a variation ina charging current based on a plurality of internal states.

FIG. 6 illustrates an example of a process of determining a variation ina charging current based on a state of charge (SOC) of a battery.

FIG. 7 is a flowchart illustrating an example of a battery chargingmethod;

FIG. 8 illustrates an example of a battery charging apparatus. and

FIG. 9 illustrates an example of a vehicle with battery charging.

Throughout the drawings and the detailed description, unless otherwisedescribed or provided, the same drawing reference numerals will beunderstood to refer to the same elements, features, and structures. Thedrawings may not be to scale, and the relative size, proportions, anddepiction of elements in the drawings may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided merelyto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.

The following specific structural or functional descriptions areexemplary to merely describe the examples, and the scope of the examplesis not limited to the descriptions provided in the presentspecification. Various changes and modifications can be made thereto bythose of ordinary skill in the art.

Although terms of “first” or “second” are used to explain variouscomponents, the components are not limited to the terms. These termsshould be used only to distinguish one component from another component.For example, a “first” component may be referred to as a “second”component, or similarly, and the “second” component may be referred toas the “first” component within the scope of the right according to theconcept of the present disclosure.

It will be understood that when a component is referred to as being“connected to” another component, the component can be directlyconnected or coupled to the other component or intervening componentsmay be present.

The terminology used herein is for describing various examples only, andis not to be used to limit the disclosure. The articles “a,” “an,” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. The terms “comprises,” “includes,”and “has” specify the presence of stated features, numbers, operations,members, elements, and/or combinations thereof, but do not preclude thepresence or addition of one or more other features, numbers, operations,members, elements, and/or combinations thereof.

Due to manufacturing techniques and/or tolerances, variations of theshapes shown in the drawings may occur. Thus, the examples describedherein are not limited to the specific shapes shown in the drawings, butinclude changes in shape that occur during manufacturing.

Unless otherwise defined herein, all terms used herein includingtechnical or scientific terms have the same meanings as those generallyunderstood by one of ordinary skill in the art with respect to thedisclosure of the present application. Terms defined in dictionariesgenerally used should be construed to have meanings matching withcontextual meanings in the related art and the present application andare not to be construed as an ideal or excessively formal meaning unlessotherwise defined herein.

Herein, it is noted that use of the term “may” with respect to anexample or embodiment, e.g., as to what an example or embodiment mayinclude or implement, means that at least one example or embodimentexists where such a feature is included or implemented while allexamples and embodiments are not limited thereto.

FIG. 1 illustrates an example of a battery system 100.

Referring to FIG. 1, the battery system 100 includes a battery chargingapparatus 110 and a battery 120, but is not limited to these components.

The battery 120 may be, for example, a battery cell, a battery module ora battery pack. The battery 120 may include a charger or a secondarycell configured to store power by receiving a charge, and a device thatincludes the battery 120 may receive the power from the battery 120, andapply the received power to a load.

The battery charging apparatus 110 is implemented by, for example, abattery management system (BMS). The BMS is a system configured tomanage the battery 120, and performs, for example, any one or anycombination of an operation of monitoring a state of charge (SOC) or astate of health (SOH) of the battery 120, an operation of maintaining anoptimized condition of the battery 120, an operation of predicting areplacement timing of the battery 120 based on a determination of thelifespan of the battery 120, an operation of detecting a fault of thebattery 120, and an operation of generating a control signal or acommand signal associated with the battery 120 to control a state oroperation of the battery 120.

The battery charging apparatus 110 determines a charging current tocharge the battery 120 for each charging operation or step. The batterycharging apparatus 110 determines a variation in the charging currentbased on a degradation condition and an internal state of the battery120 in a present charging operation or step, and reduces an amount ofthe charging current by the determined variation, to determine acharging current that is to be used for charging the battery in asubsequent charging operation.

In an example, a charging current is variously expressed in amperes (A)or milliamperes (mA). Also, the charging current is expressed by ac-rate. The c-rate is a battery-related characteristic indicating a rateof current for charging and discharging of a battery based on a capacityof the battery, and a unit of “C” is typically used. For example, when abattery has a capacity of 1,000 milliampere hour (mAh) that correspondsto an amount of current to be used, or that the battery is capable ofholding, for 1 hour, and when current for charging and discharging is 1A, the c-rate is “1 C=1 A/1,000 mAh.”

Hereinafter, an example of an operation of the battery chargingapparatus 110 will be further described with reference to the drawings.

FIG. 2 is a flowchart illustrating an example of a battery chargingmethod.

The battery charging method of FIG. 2 is performed by, for example, oneor more processors of a battery charging apparatus. The battery chargingapparatus charges a battery using a multi-step charging scheme withcharging currents in multiple steps. As a non-limiting example, in thediscussions that follow, the battery and the battery charging apparatusmay correspond to the battery charging apparatus 110 and the battery 120of FIG. 1.

Referring to FIGS. 1 and 2, in the example depicted, in operation 210,the battery charging apparatus 110 determines a variation in a chargingcurrent based on a degradation condition and an internal state of abattery 120 in a present charging step.

The internal state is a factor that has an influence on a degradationstate of a battery 120, and is estimated from any one or any combinationof a voltage, a current and a temperature of the battery based on anelectrochemical model of the battery. The internal state includes, forexample, any one or any combination of an anode overpotential, a cathodeoverpotential, an anode surface lithium ion concentration, a cathodesurface lithium ion concentration, a cell voltage condition, a state ofcharge (SOC), a state of health (SOH), and an internal temperature ofthe battery.

An overpotential is a voltage drop due to a deviation from anequilibrium potential associated with intercalation or de-intercalationreactions at each electrode of a battery. Also, a lithium ionconcentration is a concentration of lithium ions (Li+) used as amaterial in an active material of each electrode of a battery, andmaterials other than the lithium ions are used as materials in theactive material.

The SOC is a parameter indicating an amount of charge in a battery, orthe level of charge remaining in the battery. The SOC indicates a levelof energy stored in a battery and an amount of the SOC may be expressedas 0 to 100% using a percentage unit. For example, 0% indicates a fullydischarged state and 100% indicates a fully charged state, which isvariously modified and defined depending on a design intent or examples.Various schemes may be employed to estimate or measure the SOC.

To express an internal state of a battery, an electrochemical model maybe employed using various schemes or methods. For example, variousapplication models as well as a single particle model (SPM) are employedas electrochemical models. Also, parameters that define anelectrochemical model are variously modified depending on a designintent.

For example, a degradation factor of a battery is applied to anelectrochemical model that is utilized to estimate an initial state ofthe battery. The degradation factor of the battery is a factorindicating a degradation level of the battery, and includes, forexample, any one or any combination of an anode surface resistance, acathode surface resistance, a reduction in an anode active material anda reduction in a cathode active material.

The battery charging apparatus estimates a state of health (SOH) of thebattery, acquires a degradation factor of the battery based on theestimated SOH, and applies the acquired degradation factor to anelectrochemical model. The SOH is a parameter that quantitativelyrepresents a change in a life characteristic of the battery due to anaging effect (for example, a degradation phenomenon), and may indicatethe amount of charge that the battery is capable of holding. The SOHindicates, for example, a degree of degradation in a lifespan orcapacity of the battery. Various schemes for estimating or measuring anSOH are employed. In response to the degradation level of the batterybeing reflected, parameters of the electrochemical model are modified.

In operation 220, the battery charging apparatus 110 determines acharging current of a subsequent charging step based on the variation inthe charging current (based on the degradation condition and theinternal state of the battery in the present charging step) and thecharging current in the present charging step. For example, the batterycharging apparatus determines a charging current reduced by thevariation from the charging current of the present charging step, as acharging current of the next charging step.

FIG. 3 illustrates an example of a process of determining a chargingcurrent of a battery.

FIG. 3 illustrates charging currents and internal states for eachcharging step.

Referring to FIGS. 1 and 3, in the example depicted, a battery chargingapparatus 110 charges a battery 120 based on a multi-step chargingscheme with charging currents in multiple steps. For example, thebattery charging apparatus 110 charges a battery 120 with a chargingcurrent corresponding to a constant current (CC) during a singlecharging step. Also, the battery charging apparatus 110 reduces anamount of a charging current of a present charging step by a variationin the charging current, and charges the battery 120 in a subsequentcharging step based on the reduced charging current.

An internal state of the battery 120 changes during charging of thebattery 120. For example, when the internal state of the battery reachesa degradation condition, the battery is degraded. The degradationcondition is a condition related to the internal state in which thebattery 120 is degraded. For example, when an anode overpotential of thebattery 120 is reduced to 0.01 volts (V) or less, the battery 120 isdetermined to be degraded. In this example, when an anode overpotentialof 0.01 V is set as a degradation condition for a degradation of thebattery in response to the anode overpotential reaching 0.01V. Thedegradation condition is experimentally or heuristically derived, or isderived from an electrochemical model of the battery 120, however, ascheme of setting the degradation condition is not limited thereto.

As shown in the example of FIG. 3, a charging current remains unchangedalthough the internal state of the battery 120 changes during a singlecharging step. Charging currents are determined for each of the chargingsteps. The battery charging apparatus 110 determines a variation in acharging current based on a degradation condition and an internal stateof the battery 120 in a present charging step, and determines a chargingcurrent of a subsequent charging step based on the determined variationin the charging current (based on the degradation condition and theinternal state of the battery in the present charging step) and thecharging current in the present charging step.

The variation in the charging current is determined based on a rate ofchange of the internal state of the battery in the present charging stepand a difference between the internal state of the battery and thedegradation condition. For example, the variation is determined usingEquation 1 shown below.

$\begin{matrix}{{\frac{{S - C}}{\Delta\;{S/\Delta}\; t} = A}{{f(A)} = {\Delta\; I}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

In Equation 1, S denotes an internal state of a battery, C indicates adegradation condition, ΔS denotes a variation in the internal stateduring a single charging step, Δt denotes a charging time of a singlecharging step, f( ) denotes a transformation function, and ΔI denotes avariation in a charging current.

The rate of change of the internal state of the battery is determinedbased on a variation in the internal state during a single charging stepand a charging time of the charging step. Also, the difference betweenthe internal state and the degradation condition is determined. In thisexample, the internal state may have various values, for example, aminimum value, a maximum value and an average value of the internalstate in a single charging step.

As shown in Equation 1 above, a parameter A is determined based on therate of change of the internal state and the difference between theinternal state and the degradation condition, and a variation in thecharging current is determined from the parameter A using atransformation function.

The transformation function is a function in which a variation in acharging current increases as the parameter A decreases, and includes,for example, a linear function, a reciprocal function, an exponentialfunction and a Gaussian function as shown in FIG. 4. However, examplesof the transformation function are not limited thereto, and areapplicable to any function in which a variation in a charging currentincreases as a parameter A decreases in Equation 2 below.f(A)=0.2+e ^(−A/1000) =ΔI  Equation 2

Due to the transformation function, the variation in the chargingcurrent is determined to increase when the rate of change of theinternal state increases. For example, a relatively high rate of changeof the internal state of the battery indicates that the internal stateof the battery is quickly approaching the degradation condition. In thisexample, a degradation of the battery may be inhibited by increasing thevariation in the charging current.

In an example, the variation in the charging current decreases when thedifference between the internal state of the battery and the degradationcondition increases. A large difference between the internal state ofthe battery and the degradation condition may indicate that a presentinternal state of the battery is considerably different from thedegradation condition. The variation in the charging current does notnecessarily have to be increased to prevent a degradation of thebattery.

For example, when the difference between the internal state of thebattery and the degradation condition decreases, and when the rate ofchange of the internal state of the battery increases, the variation inthe charging current is determined to increase. Thus, the internal stateis allowed to slowly reach the degradation condition.

Thus, a charging waveform in which, when a degradation condition isquickly satisfied due to a charging current of a present charging step,a charging current of a subsequent charging step decreasessubstantially, is induced. In an example, if there is a slow rate ofchange of an internal state of a battery when the internal stateapproaches a degradation condition, the battery 120 is stably charged.The battery charging apparatus 110 determines charging currents for eachcharging step within a range in which the internal state does not reachthe degradation condition using the above-described method, toefficiently charge the battery.

FIG. 5 illustrates an example of a process of determining a variation ina charging current based on a plurality of internal states of a battery.

Referring to FIGS. 1 and 5, in the example depicted, a battery chargingapparatus 110 determines a variation in a charging current based on aplurality of internal states of the battery 120, for example, internalstates S₁ through S_(n). Degradation conditions C₁ through C_(n)respectively corresponding to the internal states S₁ through S_(n) areset, and parameters A₁ through A_(n) respectively corresponding to theinternal states S₁ through S_(n) are set based on the internal states S₁through S_(n) and degradation conditions C₁ through C_(n), respectively.Also, on the basis of a transformation function, individual variationsΔI₁ through ΔI_(n) in charging currents are determined from theparameters A₁ through A_(n), respectively.

The battery charging apparatus 110 determines a final variation ΔI in acharging current based on the individual variations ΔI₁ through ΔI_(n)respectively corresponding to the internal states S₁ through S_(n). Forexample, the battery charging apparatus 110 determines any one or anycombination of a maximum value, a minimum value and an average value ofthe individual variations ΔI₁ through ΔI_(n) as the final variation ΔI.Also, various methods may be used to determine the final variation ΔIbased on the individual variations ΔI₁ through ΔI_(n).

As described above, the battery charging apparatus determines the finalvariation ΔI based on the internal states S₁ through S_(n), and thus itis possible to effectively inhibit a degradation in the battery based onall various internal states.

FIG. 6 illustrates an example of a process of determining a variation ina charging current based on an SOC of a battery.

Referring to FIGS. 1 and 6, in the example depicted, a battery chargingapparatus 110 determines a variation in a charging current byselectively using an SOC of a battery 120. In general, when a battery120 is charged with a relatively high current when the battery 120 is ina relatively high SOC, a probability of a degradation in the battery isrelatively high. Thus, it would be beneficial to prevent a battery frombeing charged with a relatively high current when the battery is in arelatively high SOC state.

In an example, the battery charging apparatus 110 determines whether theSOC of the battery 120 reaches a threshold condition (for example, anSOC less than or equal to k %). For example, when the SOC reaches thethreshold condition, the battery charging apparatus 110 determines avariation in a charging current based on a degradation condition and aninternal state of the battery 120, regardless of the SOC, as describedabove.

In another example, when the SOC does not reach the threshold condition,the battery charging apparatus 110 determines a variation in a chargingcurrent based on the SOC in addition to the degradation condition andthe internal state of the battery 120. In this example, the batterycharging apparatus 110 determines the variation to be greater than avariation in a charging current that is determined based on thedegradation condition and the internal state of the battery, regardlessof the SOC. Additionally, when the SOC increases, the battery chargingapparatus 110 determines the variation in the charging current toincrease.

An example of determining a variation in a charging current when the SOCdoes not reach the threshold condition is expressed using Equation 3shown below.f(A,SOC)=ΔI  Equation 3

In Equation 3, SOC denotes an SOC of a battery.

FIG. 7 is a flowchart illustrating an example of a battery chargingmethod. The operations in FIG. 7 may be performed in the sequence andmanner as shown, although the order of some operations may be changed orsome of the operations omitted without departing from the spirit andscope of the illustrative examples described. Many of the operationsshown in FIG. 7 may be performed in parallel or concurrently. One ormore blocks of FIG. 7, and combinations of the blocks, may beimplemented by a special purpose hardware-based computer that performsthe specified functions, or combinations of special purpose hardware andcomputer instructions. In addition to the description of FIG. 7 below,the descriptions of FIG. 1 are also applicable to FIG. 7, and areincorporated herein by reference. Thus, the above description may not berepeated here.

The battery charging method of FIG. 7 is performed by, for example, oneor more processors of a battery charging apparatus.

Referring to the example depicted in FIG. 7, in operation 711, thebattery charging apparatus 110 determines an initial charging currentI₁. As a non-limiting example, the initial charging current I₁ isexperimentally or heuristically determined by a battery cellmanufacturer or a user of a battery, and a scheme of determining theinitial charging current I₁ is not limited thereto.

In operation 713, the battery charging apparatus sets a charging step to“1.”

In operation 715, the battery charging apparatus charges a battery witha charging current I_(N) that corresponds to a CC.

In operation 717, the battery charging apparatus 110 measures any one orany combination of a current, a voltage and a temperature of thebattery, and estimates an internal state of the battery based on ameasured value and an electrochemical model, during a charging processof the battery.

In operation 719, the battery charging apparatus 110 determines whethera charging termination condition is satisfied. The charging terminationcondition is a condition to terminate charging of the battery 120. Forexample, a charging termination condition is set for any one or anycombination of a charging time, a current, a voltage, a temperature andan internal state of the battery 120. The battery charging apparatus 110determines whether a value obtained by measuring the charging time, thecurrent, the voltage or the temperature, and/or a value obtained byestimating the internal state of the battery reaches the chargingtermination condition.

In an example, the battery charging apparatus 110 determines whether acharging time of the battery 120 reaches a charging terminationcondition (for example, a charging time longer than or equal to 1 hour).In another example, the battery charging apparatus 110 determineswhether an SOC of the battery 120 reaches a charging terminationcondition (for example, an SOC greater than or equal to 95%). In stillanother example, the battery charging apparatus 110 determines whethereach of the charging time and the SOC of the battery 120 reaches acharging termination condition.

When the charging termination condition is not satisfied, the batterycharging apparatus 110 determines whether a charging limit condition issatisfied in operation 721. The charging limit condition is a conditionto divide charging of the battery 120 into a plurality of charging stepsto charge the battery 120 within a range to prevent a degradation of thebattery. For example, a charging limit condition for any one or anycombination of a charging time, a current, a voltage, a temperature andan internal state of the battery is set. The battery charging apparatus110 determines whether a value obtained by measuring the charging time,the current, the voltage or the temperature, and/or a value obtained byestimating the internal state of the battery reaches the charging limitcondition.

In an example, the battery charging apparatus 110 determines whether acharging time of the battery 120 reaches a charging limit condition (forexample, a charging time longer than or equal to 8 minutes). In anotherexample, the battery charging apparatus 110 determines whether avariation in the internal state of the battery 120 reaches a charginglimit condition (for example, a variation higher than or equal to 0.1V). In still another example, the battery charging apparatus 110determines whether each of the charging time and the variation in theinternal state reaches a charging limit condition.

When the charging limit condition is not satisfied, operations 715through 721 are reperformed.

When the charging limit condition is satisfied, the battery chargingapparatus 110 calculates a parameter A based on a rate of change of theinternal state of the battery in a corresponding charging step and adifference between the internal state of the battery and the degradationcondition in operation 723.

In operation 725, the battery charging apparatus 110 determines avariation in a charging current (for example, indicated by ΔI_(N)) fromthe parameter A using a transformation function. The transformationfunction is a function in which a variation in a charging currentincreases as the parameter A decreases, and includes, for example, alinear function, a reciprocal function, an exponential function and aGaussian function.

In operation 727, the battery charging apparatus 110 reduces a chargingcurrent of a corresponding charging step by the variation determined inoperation 725, to determine a charging current of a subsequent chargingstep.

In operation 729, the battery charging apparatus 110 increments acharging step by “1.”In operation 715, the battery charging apparatus110 charges the battery 120 with the charging current determined inoperation 727.

When the charging termination condition is satisfied in operation 719,the battery charging method of FIG. 7 is terminated.

FIG. 8 illustrates an example of a battery charging apparatus 800.

Referring to FIG. 8, as a non-limiting example, the battery chargingapparatus 800 includes a memory 810 and a processor 820. The memory 810and the processor 820 communicate with each other via a bus 830.Although only a single memory 810 and a single processor 820 areillustrated in FIG. 8, this is only an example. The battery chargingapparatus 800 may include one or more memories 810, and one or moreprocessors 820.

The memory 810 stores a computer-readable instruction. The processor 820performs the above-described operations in response to the instructionin the memory 810 being executed by the processor 820. The memory 810is, for example, a volatile memory or a non-volatile memory.

The processor 820 includes an apparatus configured to executeinstructions or programs or to control the battery charging apparatus800. The processor 820 determines a variation in a charging current tocharge a battery based on a degradation condition of the battery and aninternal state of the battery in a present charging step, and determinesa charging current of a subsequent charging step based on the variationin the charging current (based on the degradation condition and theinternal state of the battery in the present charging step) and thecharging current in the present charging step.

As a non-limiting example, the battery charging apparatus 800 isincluded in, for example, various electronic devices (for example, anelectric vehicle, a walking assistance apparatus, a drone, or a mobileterminal) that use a battery as a power source, and performs theoperations described above with reference to FIGS. 1 through 7.Hereinafter, an example in which the battery charging apparatus 800 isincluded in an electric vehicle is described with reference to FIG. 9.

FIG. 9 illustrates an example of a vehicle 900.

Referring to FIG. 9, in the example depicted, the vehicle 900 includes abattery pack 910 and a BMS 920. The vehicle 900 may use the battery pack910 as a power source. As a non-limiting example, the vehicle 900 maybe, for example, an electric vehicle (EV) or a hybrid vehicle.

The battery pack 910 includes at least one battery module. The batterymodule includes at least one battery cell.

The BMS 920 monitors whether an abnormality occurs in the battery pack910, and may prevent the battery pack 910 from being overcharged orover-discharged. Also, the BMS 920 performs a thermal control on thebattery pack 910 when a temperature of the battery pack 910 exceeds afirst temperature (for example, 40° C.) or is less than a secondtemperature (for example, −10° C.). Furthermore, the BMS 920 performscell balancing to equalize SOCs of battery cells included in the batterypack 910.

For example, the BMS 920 includes a battery charging apparatus. The BMS920 determines, using the battery charging apparatus, a variation in acharging current to charge a battery based on a degradation conditionand an internal state of the battery in a present charging step, todetermine a charging current of a subsequent charging step.

The above description of FIGS. 1 through 8 is also applicable to theexample of FIG. 9, and accordingly is not repeated here.

The battery system 100, the battery charging apparatus 800, the BMS 920and other apparatuses, units, modules, devices, and other componentsdescribed herein with respect to FIGS. 1, 3 through 6, 8 and 9 areimplemented by hardware components. Examples of hardware components thatmay be used to perform the operations described in this applicationwhere appropriate include controllers, sensors, generators, drivers,memories, comparators, arithmetic logic units, adders, subtractors,multipliers, dividers, integrators, and any other electronic componentsconfigured to perform the operations described in this application. Inother examples, one or more of the hardware components that perform theoperations described in this application are implemented by computinghardware, for example, by one or more processors or computers. Aprocessor or computer may be implemented by one or more processingelements, such as an array of logic gates, a controller and anarithmetic logic unit, a digital signal processor, a microcomputer, aprogrammable logic controller, a field-programmable gate array, aprogrammable logic array, a microprocessor, or any other device orcombination of devices that is configured to respond to and executeinstructions in a defined manner to achieve a desired result. In oneexample, a processor or computer includes, or is connected to, one ormore memories storing instructions or software that are executed by theprocessor or computer. Hardware components implemented by a processor orcomputer may execute instructions or software, such as an operatingsystem (OS) and one or more software applications that run on the OS, toperform the operations described in this application. The hardwarecomponents may also access, manipulate, process, create, and store datain response to execution of the instructions or software. Forsimplicity, the singular term “processor” or “computer” may be used inthe description of the examples described in this application, but inother examples multiple processors or computers may be used, or aprocessor or computer may include multiple processing elements, ormultiple types of processing elements, or both. For example, a singlehardware component or two or more hardware components may be implementedby a single processor, or two or more processors, or a processor and acontroller. One or more hardware components may be implemented by one ormore processors, or a processor and a controller, and one or more otherhardware components may be implemented by one or more other processors,or another processor and another controller. One or more processors, ora processor and a controller, may implement a single hardware component,or two or more hardware components. A hardware component may have anyone or more of different processing configurations, examples of whichinclude a single processor, independent processors, parallel processors,single-instruction single-data (SISD) multiprocessing,single-instruction multiple-data (SIMD) multiprocessing,multiple-instruction single-data (MISD) multiprocessing, andmultiple-instruction multiple-data (MIMD) multiprocessing.

The methods illustrated in FIGS. 2 and 7 that perform the operationsdescribed in this application are performed by computing hardware, forexample, by one or more processors or computers, implemented asdescribed above executing instructions or software to perform theoperations described in this application that are performed by themethods. For example, a single operation or two or more operations maybe performed by a single processor, or two or more processors, or aprocessor and a controller. One or more operations may be performed byone or more processors, or a processor and a controller, and one or moreother operations may be performed by one or more other processors, oranother processor and another controller. One or more processors, or aprocessor and a controller, may perform a single operation, or two ormore operations.

Instructions or software to control a processor or computer to implementthe hardware components and perform the methods as described above arewritten as computer programs, code segments, instructions or anycombination thereof, for individually or collectively instructing orconfiguring the processor or computer to operate as a machine orspecial-purpose computer to perform the operations performed by thehardware components and the methods as described above. In one example,the instructions or software include machine code that is directlyexecuted by the processor or computer, such as machine code produced bya compiler. In another example, the instructions or software includehigher-level code that is executed by the processor or computer using aninterpreter. The instructions or software may be written using anyprogramming language based on the block diagrams and the flow chartsillustrated in the drawings and the corresponding descriptions in thespecification, which disclose algorithms for performing the operationsthat are performed by the hardware components and the methods asdescribed above.

The instructions or software to control computing hardware, for example,one or more processors or computers, to implement the hardwarecomponents and perform the methods as described above, and anyassociated data, data files, and data structures, are recorded, stored,or fixed in or on one or more non-transitory computer-readable storagemedia. Examples of a non-transitory computer-readable storage mediuminclude read-only memory (ROM), random-access programmable read onlymemory (PROM), electrically erasable programmable read-only memory(EEPROM), random-access memory (RAM), dynamic random access memory(DRAM), static random access memory (SRAM), flash memory, non-volatilememory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs,DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, blue-rayor optical disk storage, hard disk drive (HDD), solid state drive (SSD),flash memory, a card type memory such as multimedia card micro or a card(for example, secure digital (SD) or extreme digital (XD)), magnetictapes, floppy disks, magneto-optical data storage devices, optical datastorage devices, hard disks, solid-state disks, and any other devicethat is configured to store the instructions or software and anyassociated data, data files, and data structures in a non-transitorymanner and provide the instructions or software and any associated data,data files, and data structures to one or more processors or computersso that the one or more processors or computers can execute theinstructions. In one example, the instructions or software and anyassociated data, data files, and data structures are distributed overnetwork-coupled computer systems so that the instructions and softwareand any associated data, data files, and data structures are stored,accessed, and executed in a distributed fashion by the one or moreprocessors or computers.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. A battery charging method comprising:determining, in a present charging operation, a variation in a chargingcurrent to charge a battery based on a degradation condition of thebattery and an internal state of the battery in the present chargingoperation; and determining a charging current of a subsequent chargingoperation based on the determined variation in the charging current inthe present charging operation and the charging current in the presentcharging operation, wherein the determining of the variation in thecharging current comprises determining the variation based on a rate ofchange of the internal state of the battery in the present chargingoperation, and a difference between the internal state of the batteryand the degradation condition.
 2. The battery charging method of claim1, wherein the determining of the variation in the charging currentfurther comprises determining the variation to increase in response tothe rate of change of the internal state of the battery in the presentcharging operation increasing.
 3. The battery charging method of claim1, wherein the determining of the variation in the charging currentfurther comprises determining the variation to decrease in response tothe difference between the internal state and the degradation conditionincreasing.
 4. The battery charging method of claim 1, wherein thedetermining of the variation in the charging current comprisesdetermining the variation based on a state of charge (SOC) of thebattery.
 5. The battery charging method of claim 4, wherein thedetermining of the variation in the charging current comprises: inresponse to the SOC reaching a threshold condition, determining thevariation in the charging current based on the internal state of thebattery and the degradation condition; and in response to the SOC notreaching the threshold condition, determining the variation in thecharging current based on the SOC, the internal state of the battery,and the degradation condition, wherein the variation in the chargingcurrent is greater when the SOC has not reached the threshold condition.6. The battery charging method of claim 1, wherein the internal state ofthe battery comprises two or more of an anode overpotential, a cathodeoverpotential, an anode surface lithium ion concentration, a cathodesurface lithium ion concentration, a cell voltage condition, an SOC anda temperature of the battery, and the determining of the variation inthe charging current comprises: determining variations in chargingcurrents for each of a plurality of internal states; and finallydetermining the variation in the charging current based on thedetermined variations for each of the plurality of internal states. 7.The battery charging method of claim 1, wherein the determining of thevariation in the charging current comprises: determining whether acharging limit condition is satisfied during charging of the battery inthe present charging operation; and determining the variation in thecharging current based on the internal state of the battery and thedegradation condition, in response to the charging limit condition beingsatisfied.
 8. The battery charging method of claim 7, wherein thecharging limit condition is a condition to divide charging of thebattery into a plurality of charging operations to charge the batterywithin a range in which a degradation of the battery is prevented. 9.The battery charging method of claim 1, wherein the internal state ofthe battery is a factor that controls on the degradation condition ofthe battery, and the internal state is estimated from one or more of acurrent, a voltage and a temperature of the battery based on anelectrochemical model of the battery.
 10. The battery charging method ofclaim 9, wherein the electrochemical model is a model to which adegradation factor of the battery is applied.
 11. The battery chargingmethod of claim 10, wherein the degradation factor comprises one or moreof an anode surface resistance, a cathode surface resistance, areduction in an anode active material and a reduction in a cathodeactive material.
 12. The battery charging method of claim 1, furthercomprising: charging the battery with the charging current of thesubsequent charging operation.
 13. The battery charging method of claim1, further comprising: determining whether one or more of a chargingtime, a current, a voltage, a temperature and the internal state of thebattery reaches a charging termination condition; and terminatingcharging of the battery in response to the charging terminationcondition being satisfied.
 14. A non-transitory computer-readablestorage medium storing instructions that, when executed by a processor,cause the processor to perform the method of claim
 1. 15. A batterycharging apparatus comprising: a processor; and a memory configured tostore at least one instruction that is executable by the processor,wherein in response to the at least one instruction being executed bythe processor, the processor is configured to determine, in a presentcharging operation, a variation in a charging current to charge abattery based on a degradation condition of the battery and an internalstate of the battery in the present charging operation, and configuredto determine a charging current of a subsequent charging operation basedon the variation in the charging current in the present chargingoperation and the charging current in the present charging operation,wherein the processor is configured to determine the variation in thecharging current based on a rate of change of the internal state of thebattery in the present charging operation, and a difference between theinternal state of the battery and the degradation condition.
 16. Thebattery charging apparatus of claim 15, wherein the processor is furtherconfigured to determine the variation in the charging current based on astate of charge (SOC) of the battery.
 17. The battery charging apparatusof claim 16, wherein the internal state of the battery comprises any twoor any combination of an anode overpotential, a cathode overpotential,an anode surface lithium ion concentration, a cathode surface lithiumion concentration, a cell voltage condition, an SOC and a temperature ofthe battery, and the processor is configured to determine variations incharging currents for each of a plurality of internal states, and tofinally determine the variation in the charging current based on thedetermined variations for each of the plurality of internal states. 18.The battery charging apparatus of claim 16, wherein the processor isconfigured to determine whether a charging limit condition is satisfiedduring charging of the battery in the present charging operation, andconfigured to determine the variation in the charging current based onthe internal state of the battery and the degradation condition, inresponse to the charging limit condition being satisfied.